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Solving turbulence in a room

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Old   November 9, 2018, 17:59
Question Solving turbulence in a room
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Hi everyone,

I'm modelling the air flow in a room.

I successfully modelled the flow using simpleFoam without turbulence but when turning turbulence on, the solver diverges.

The turbulence fields are diverging starting at the edges between inlet/outlet and the air duct (wall). So I thought it is a stl problem according to the following post :

https://www.cfd-online.com/Forums/op...sh-salome.html

I tried different methods to optimise my mesh. For example, I used the tool surfaceMeshTriangulate to generate a waterproof mesh.

The solver still diverges almost immediately. So I'm muddled. Are the boundary conditions right configured ? Is there a problem in the settings of fvSchemes and fvSolution ?

Could any experienced user of snappyHexMesh and openFoam have a look and give my some hints please ? Is there a problem in the mesh generation ? In the stl files ? BCs ? Solvers settings ?

You can obtain my case following this link (8Mo) :

https://we.tl/t-KT2wBkQ89d

After downloading and extracting, just copy, paste and run :

./Allclean && cp -r 0.orig/ 0 && blockMesh | tee log.blockMesh && surfaceFeatureExtract | tee log.surfaceFeatureExtract && snappyHexMesh -overwrite | tee log.snappyHexMesh && checkMesh | tee log.checkMesh && potentialFoam | tee log.potentialFoam && simpleFoam | tee log.simpleFoam && simpleFoam -postProcess -func yPlus | tee log.simpleFoamYPlusRAS


Have a nice weekend all !

jipai

Last edited by jipai; November 11, 2018 at 09:17.
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Old   November 25, 2018, 17:01
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abdikerim kurbanaliev
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Hi, jipai


Could you send your's case file once more time? previous was deleted.
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Old   November 25, 2018, 17:35
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Hi Kerim,

Thank you for the reply .

I sent you a new link :
https://we.tl/t-OAWBmEfvgd

Jipai
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Old   November 25, 2018, 20:23
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abdikerim kurbanaliev
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Thanks a lot!
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Old   November 26, 2018, 05:16
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Hi, I am also doing a airflow in room. Could you upload case file in google drive or github. I couldn't open the link.

or just post your files here..!

Thanks,
ssa.
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Old   November 26, 2018, 09:54
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Hi ssa,

I shared the files on google drive. Please try this link :
https://drive.google.com/file/d/1c_l...ew?usp=sharing

The files takes 8Mo so cfd-online doesn't accept it

Have a nice day
jipai
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Old   November 26, 2018, 10:24
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I just saw your files and here is the quick review.

You are using nutKwallfunction for k. use kqrwallfunction.
use wall function for nut.

From my opinion, try to use pimplefoam or pisofoam with RANS.

If you are running RANS, use upwind scheme for k,epsilon and omega. Don't use limitedlinear. If upwind works well, then change to linearupwind or other schemes.
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Old   November 26, 2018, 16:51
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OK for kqRWallFunction

You're right about upwind scheme. It converges much better than limitedLinear (I actually manage to make the case converge with limitedLinear but with relaxation factors lowered to 0.5)

I will try to run with pimpleFoam or pisoFoam. I'm not yet familiar with transient similations with OpenFoam, but let's give it a try ^^

Many thanks for your hints
Regards

jipai
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